Power/Area Efficient Low Noise Amplifier for Ultra-Low Amplitude Recording from Amputee Intrafascicular Nerve

Advanced hand-prostheses that can be interfaced directly with the nervous system are being developed to capture motor intent from upper limb amputees. One approach is to record neural activity of peripheral nerves (PN) in the residual limb using longitudinal intrafascicular electrodes (LIFEs). LIFE recordings using commercial recording systems from amputated human nerves show broad spikes with amplitudes in the low microvolt ranges. Current custom integrated circuits for PN recording using cuffs that include a low noise amplifier, are not monolithic and do not meet the power/area requirements for an embedded system. We are designing an implantable neural recording amplifier for LIFEs that meets the low noise and low power/area consumption specifications for low amplitude recordings. The post-layout performance from Monte Carlo simulations indicates that we can achieve a mid-gain of 36.7±0.9% dB, input-referred noise of 2.3±7% μVrms on 10-10k Hz at 37^oC, power of 194±3% μW. The low noise amplifier area is 0.15mm², designed with a 0.18μm CMOS process. This design offers lower power/area consumption for equivalent noise performance of the integrated circuits for cuff recordings.